Electrically variable transmissions, such as those described in U.S. Pat. No. 5,931,757, employ two electric motors mounted inside a transmission housing. The electric motors are coaxially oriented with an input shaft, an output shaft, and two planetary gearsets. Each motor is operatively connected to a member of one of the planetary gearsets to provide a range or mode of transmission operation characterized by a continuously variable speed ratio between the input shaft and the output shaft.
The electric motors in electrically variable transmissions must have very precise location, low sensitivity of location to thermal events, and very uniform coolant flow. Thus, manufacturing tolerances for components, such as the housing, that interface with the motors are typically small and, accordingly, limit the manufacturing processes that may be employed.